1. Field of the Invention
The present invention relates to a cyan ink for ink-jet recording.
2. Description of the Related Art
In an ink-jet recording method, a cyan ink is required in order to form a full-color image. Generally known examples of the cyan dye used as a coloring agent in such a cyan ink include C. I. Acid Blue 74, C. I. Acid Blue 9 and the like. However, since these cyan dyes have very poor light fastness, copper phthalocyanine-based dyes such as C. I. Direct Blue 86, C. I. Direct Blue 199 and the like are widely employed as the coloring agent of the cyan ink used in commercial ink-jet inks. These common copper phthalocyanine-based dyes are characterized by having better light fastness than magenta dyes and yellow dyes. However, these phthalocyanine-based dyes are prone to fading or discoloring due to contact with ozone. Thus a problem exists in that discoloration or optical density reduction occurs in an ink-jet recorded image recorded with these dyes. In view of the above, a copper phthalocyanine-based dye has been proposed which has improved ozone resistance (see Japanese Patent Application Laid-Open No. Hei 03-103484).
However, even when such a copper phthalocyanine-based dye having improved ozone resistance is employed, a cyan ink for ink-jet recording having excellent hue, excellent light fastness, ozone resistance and ejection stability has not been realized up until now.